In Africa, more than 4 million people suffer from active tuberculosis (TB) resulting in an estimated 650,000 deaths every year. The etiologic agent of TB, Mycobacterium tuberculosis, survives in resting macrophages, which control the pathogen after activation by specific T lymphocytes. Here, we describe the basic mechanisms underlying the host response to TB with an emphasis on immunity and discuss diagnostics, drugs, and vaccines for TB. Moreover, we outline our attempts to develop biomarkers, which could help the monitoring of TB clinical trials, provide the basis for new diagnostics, and allow prognosis of outcome of infection and of drug treatment.